Infusion pump devices and systems are relatively well-known in the medical arts, for use in delivering or dispensing an agent, such as insulin or another prescribed medication, to a patient. A typical infusion pump includes a pump drive system which typically includes a small motor and drive train components that convert rotational motor motion to a translational displacement of a stopper (or plunger) in a reservoir. The reservoir cooperates with tubing, a catheter and/or an infusion set to create a fluid path for carrying medication from the reservoir to the body of a user. Some fluid infusion devices also include a force sensor designed to detect and indicate a pump malfunction and/or non-delivery of the medication to the patient due to a fluid path occlusion.
Stepper motors may be used to displace the stopper by a precise amount, and thereby control the dosage administered to a user. Traditionally, a stepper motor is supplied with a direct current (DC) voltage to control and/or maintain position, and thus, the stepper motor continuously consumes power during use. Additionally, stepper motors are frequently controlled using an open-loop control scheme, where the voltage applied to the stepper motor is chosen to be large enough to ensure the stepper motor provides torque that meets or exceeds the likely maximum requirements of the system, thereby ensuring that the stepper motor achieves a number of commanded steps and obviating the need for feedback mechanisms to monitor the position. However, most infusion pump devices and other portable medical devices are battery powered, and accordingly, it is desirable to reduce the power consumption of the stepper motor and prolong battery life.